What a CoA is
A Certificate of Analysis (CoA) is a document that reports analytical results for a defined batch or lot of material. In research peptide supply, a CoA is commonly used for procurement records, internal quality files, and experimental documentation.
CoAs are prepared by a testing laboratory (internal or third-party) under the methods and reporting conventions of that lab. Formats, test panels, and wording vary by vendor and testing provider. A CoA is not a marketing brochure and is not a statement of suitability for every experimental design.
Typical fields on a peptide CoA
The following fields appear frequently. Not every CoA includes every field; always read the document you receive for that lot.
| Field | What it usually means |
|---|---|
| Lot / batch number | Unique identifier for the tested material. Must match the lot printed on the vial or packaging for the result to apply to your unit. |
| Product / compound name | Name used by the supplier or testing lab. Confirm it matches the material you ordered (including salt form when relevant). |
| Identity methods (HPLC / MS) | High-performance liquid chromatography (HPLC) and mass spectrometry (MS) are commonly used. HPLC contributes a chromatographic profile; MS supports molecular mass / identity interpretation. See our HPLC and MS guide. |
| Purity (if reported) | Often expressed as HPLC area percent under stated conditions. Method-dependent; not always free-base peptide content. See Understanding Peptide Purity Claims. |
| Appearance | Visual description of the material as received for testing (e.g., lyophilized powder color/form). Subjective and condition-dependent. |
| Residual solvents | When reported, results for selected process solvents under the lab’s methods and limits. Panel and limits are method-defined. |
| Water content | When reported (e.g., Karl Fischer), moisture associated with the tested sample. Peptides can be hygroscopic; handling after opening is separate from the CoA snapshot. |
| Analysis / report date | When testing was performed or the report was issued. Useful for records and for judging how current the documentation is relative to your receipt date. |
| Testing laboratory | Name of the lab that generated the results. Contact and accreditation details, if any, appear only when the lab includes them on the report. |
Matching a CoA lot to a vial
- Locate the lot (or batch) number on the vial label and/or secondary packaging.
- Confirm the same lot number appears on the CoA you received or requested.
- Confirm product name and, when applicable, vial size or catalog identifier match your order records.
- File the CoA with your laboratory procurement or quality documentation system.
If the lot numbers do not match, the CoA does not describe that vial. Request documentation for the correct lot via our CoA / lot lookup page.
Limitations of a single CoA
- Results apply to the tested lot under the methods and conditions stated—not to every experimental use case.
- Purity and related values are method-dependent; comparing numbers across vendors without method context can mislead.
- A CoA does not certify that material is suitable for clinical, diagnostic, or human use. VialVibes materials are research use only.
- Storage, reconstitution, and laboratory handling after receipt can affect material performance in assays even when CoA data are complete for the original lot.
- Institutional policy may require independent verification beyond supplier documentation.
When to request a CoA from a vendor
Common laboratory situations include:
- Procurement or receiving inspection for a new lot;
- Institutional or grant documentation requirements;
- Method development or publication records that need lot-level analytical context;
- Comparing identity/purity reporting approaches across suppliers (with method awareness).
At VialVibes, CoAs are provided when available for the requested lot. Use the CoA request form or email research@vialvibes.com with your lot number and product name.